1. Field of the Invention
The present invention relates generally to methods for altering gene expression in a cell or an animal using viral constructs engineered to deliver an RNA molecule. In a more specific aspect, a viral construct is used to deliver double-stranded RNA molecules that can be used to down-regulate or modulate gene expression.
2. Description of the Related Art
RNA interference (RNAi) or silencing is a recently discovered phenomenon (A. Fire et al., Nature 391, 806 (1998); C. E. Rocheleau et al. Cell 90, 707 (1997)). Small interfering RNAs (“siRNAs”) are double-stranded RNA molecules that inhibit the expression of a gene with which they share homology. siRNAs have been used as a tool to down regulate the expression of specific genes in a variety of cultured cells as well as in invertebrate animals. A number of such approaches have been reviewed recently (P. D. Zamore Science 296, 1265 (2002)); however, such approaches have limitations. For example, no technique prior to the invention described herein allows for the generation of transgenic mammal having a specific gene down regulated through RNA interference. Similarly, there is a need for more robust methods for the introduction of small RNA molecules with regulatory function. The invention provided herein addresses these and other limitations in the field of RNA mediated gene regulation.